1 #ifndef _SCSI_SCSI_HOST_H 2 #define _SCSI_SCSI_HOST_H 3 4 #include <linux/device.h> 5 #include <linux/list.h> 6 #include <linux/types.h> 7 #include <linux/workqueue.h> 8 9 struct block_device; 10 struct module; 11 struct scsi_cmnd; 12 struct scsi_device; 13 struct Scsi_Host; 14 struct scsi_host_cmd_pool; 15 struct scsi_transport_template; 16 17 18 /* 19 * The various choices mean: 20 * NONE: Self evident. Host adapter is not capable of scatter-gather. 21 * ALL: Means that the host adapter module can do scatter-gather, 22 * and that there is no limit to the size of the table to which 23 * we scatter/gather data. 24 * Anything else: Indicates the maximum number of chains that can be 25 * used in one scatter-gather request. 26 */ 27 #define SG_NONE 0 28 #define SG_ALL 0xff 29 30 31 #define DISABLE_CLUSTERING 0 32 #define ENABLE_CLUSTERING 1 33 34 enum scsi_eh_timer_return { 35 EH_NOT_HANDLED, 36 EH_HANDLED, 37 EH_RESET_TIMER, 38 }; 39 40 41 struct scsi_host_template { 42 struct module *module; 43 const char *name; 44 45 /* 46 * Used to initialize old-style drivers. For new-style drivers 47 * just perform all work in your module initialization function. 48 * 49 * Status: OBSOLETE 50 */ 51 int (* detect)(struct scsi_host_template *); 52 53 /* 54 * Used as unload callback for hosts with old-style drivers. 55 * 56 * Status: OBSOLETE 57 */ 58 int (* release)(struct Scsi_Host *); 59 60 /* 61 * The info function will return whatever useful information the 62 * developer sees fit. If not provided, then the name field will 63 * be used instead. 64 * 65 * Status: OPTIONAL 66 */ 67 const char *(* info)(struct Scsi_Host *); 68 69 /* 70 * Ioctl interface 71 * 72 * Status: OPTIONAL 73 */ 74 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 75 76 77 #ifdef CONFIG_COMPAT 78 /* 79 * Compat handler. Handle 32bit ABI. 80 * When unknown ioctl is passed return -ENOIOCTLCMD. 81 * 82 * Status: OPTIONAL 83 */ 84 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 85 #endif 86 87 /* 88 * The queuecommand function is used to queue up a scsi 89 * command block to the LLDD. When the driver finished 90 * processing the command the done callback is invoked. 91 * 92 * If queuecommand returns 0, then the HBA has accepted the 93 * command. The done() function must be called on the command 94 * when the driver has finished with it. (you may call done on the 95 * command before queuecommand returns, but in this case you 96 * *must* return 0 from queuecommand). 97 * 98 * Queuecommand may also reject the command, in which case it may 99 * not touch the command and must not call done() for it. 100 * 101 * There are two possible rejection returns: 102 * 103 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but 104 * allow commands to other devices serviced by this host. 105 * 106 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this 107 * host temporarily. 108 * 109 * For compatibility, any other non-zero return is treated the 110 * same as SCSI_MLQUEUE_HOST_BUSY. 111 * 112 * NOTE: "temporarily" means either until the next command for# 113 * this device/host completes, or a period of time determined by 114 * I/O pressure in the system if there are no other outstanding 115 * commands. 116 * 117 * STATUS: REQUIRED 118 */ 119 int (* queuecommand)(struct scsi_cmnd *, 120 void (*done)(struct scsi_cmnd *)); 121 122 /* 123 * This is an error handling strategy routine. You don't need to 124 * define one of these if you don't want to - there is a default 125 * routine that is present that should work in most cases. For those 126 * driver authors that have the inclination and ability to write their 127 * own strategy routine, this is where it is specified. Note - the 128 * strategy routine is *ALWAYS* run in the context of the kernel eh 129 * thread. Thus you are guaranteed to *NOT* be in an interrupt 130 * handler when you execute this, and you are also guaranteed to 131 * *NOT* have any other commands being queued while you are in the 132 * strategy routine. When you return from this function, operations 133 * return to normal. 134 * 135 * See scsi_error.c scsi_unjam_host for additional comments about 136 * what this function should and should not be attempting to do. 137 * 138 * Status: REQUIRED (at least one of them) 139 */ 140 int (* eh_strategy_handler)(struct Scsi_Host *); 141 int (* eh_abort_handler)(struct scsi_cmnd *); 142 int (* eh_device_reset_handler)(struct scsi_cmnd *); 143 int (* eh_bus_reset_handler)(struct scsi_cmnd *); 144 int (* eh_host_reset_handler)(struct scsi_cmnd *); 145 146 /* 147 * This is an optional routine to notify the host that the scsi 148 * timer just fired. The returns tell the timer routine what to 149 * do about this: 150 * 151 * EH_HANDLED: I fixed the error, please complete the command 152 * EH_RESET_TIMER: I need more time, reset the timer and 153 * begin counting again 154 * EH_NOT_HANDLED Begin normal error recovery 155 * 156 * Status: OPTIONAL 157 */ 158 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); 159 160 /* 161 * Before the mid layer attempts to scan for a new device where none 162 * currently exists, it will call this entry in your driver. Should 163 * your driver need to allocate any structs or perform any other init 164 * items in order to send commands to a currently unused target/lun 165 * combo, then this is where you can perform those allocations. This 166 * is specifically so that drivers won't have to perform any kind of 167 * "is this a new device" checks in their queuecommand routine, 168 * thereby making the hot path a bit quicker. 169 * 170 * Return values: 0 on success, non-0 on failure 171 * 172 * Deallocation: If we didn't find any devices at this ID, you will 173 * get an immediate call to slave_destroy(). If we find something 174 * here then you will get a call to slave_configure(), then the 175 * device will be used for however long it is kept around, then when 176 * the device is removed from the system (or * possibly at reboot 177 * time), you will then get a call to slave_destroy(). This is 178 * assuming you implement slave_configure and slave_destroy. 179 * However, if you allocate memory and hang it off the device struct, 180 * then you must implement the slave_destroy() routine at a minimum 181 * in order to avoid leaking memory 182 * each time a device is tore down. 183 * 184 * Status: OPTIONAL 185 */ 186 int (* slave_alloc)(struct scsi_device *); 187 188 /* 189 * Once the device has responded to an INQUIRY and we know the 190 * device is online, we call into the low level driver with the 191 * struct scsi_device *. If the low level device driver implements 192 * this function, it *must* perform the task of setting the queue 193 * depth on the device. All other tasks are optional and depend 194 * on what the driver supports and various implementation details. 195 * 196 * Things currently recommended to be handled at this time include: 197 * 198 * 1. Setting the device queue depth. Proper setting of this is 199 * described in the comments for scsi_adjust_queue_depth. 200 * 2. Determining if the device supports the various synchronous 201 * negotiation protocols. The device struct will already have 202 * responded to INQUIRY and the results of the standard items 203 * will have been shoved into the various device flag bits, eg. 204 * device->sdtr will be true if the device supports SDTR messages. 205 * 3. Allocating command structs that the device will need. 206 * 4. Setting the default timeout on this device (if needed). 207 * 5. Anything else the low level driver might want to do on a device 208 * specific setup basis... 209 * 6. Return 0 on success, non-0 on error. The device will be marked 210 * as offline on error so that no access will occur. If you return 211 * non-0, your slave_destroy routine will never get called for this 212 * device, so don't leave any loose memory hanging around, clean 213 * up after yourself before returning non-0 214 * 215 * Status: OPTIONAL 216 */ 217 int (* slave_configure)(struct scsi_device *); 218 219 /* 220 * Immediately prior to deallocating the device and after all activity 221 * has ceased the mid layer calls this point so that the low level 222 * driver may completely detach itself from the scsi device and vice 223 * versa. The low level driver is responsible for freeing any memory 224 * it allocated in the slave_alloc or slave_configure calls. 225 * 226 * Status: OPTIONAL 227 */ 228 void (* slave_destroy)(struct scsi_device *); 229 230 /* 231 * fill in this function to allow the queue depth of this host 232 * to be changeable (on a per device basis). returns either 233 * the current queue depth setting (may be different from what 234 * was passed in) or an error. An error should only be 235 * returned if the requested depth is legal but the driver was 236 * unable to set it. If the requested depth is illegal, the 237 * driver should set and return the closest legal queue depth. 238 * 239 */ 240 int (* change_queue_depth)(struct scsi_device *, int); 241 242 /* 243 * fill in this function to allow the changing of tag types 244 * (this also allows the enabling/disabling of tag command 245 * queueing). An error should only be returned if something 246 * went wrong in the driver while trying to set the tag type. 247 * If the driver doesn't support the requested tag type, then 248 * it should set the closest type it does support without 249 * returning an error. Returns the actual tag type set. 250 */ 251 int (* change_queue_type)(struct scsi_device *, int); 252 253 /* 254 * This function determines the bios parameters for a given 255 * harddisk. These tend to be numbers that are made up by 256 * the host adapter. Parameters: 257 * size, device, list (heads, sectors, cylinders) 258 * 259 * Status: OPTIONAL */ 260 int (* bios_param)(struct scsi_device *, struct block_device *, 261 sector_t, int []); 262 263 /* 264 * Can be used to export driver statistics and other infos to the 265 * world outside the kernel ie. userspace and it also provides an 266 * interface to feed the driver with information. 267 * 268 * Status: OBSOLETE 269 */ 270 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); 271 272 /* 273 * Name of proc directory 274 */ 275 char *proc_name; 276 277 /* 278 * Used to store the procfs directory if a driver implements the 279 * proc_info method. 280 */ 281 struct proc_dir_entry *proc_dir; 282 283 /* 284 * This determines if we will use a non-interrupt driven 285 * or an interrupt driven scheme, It is set to the maximum number 286 * of simultaneous commands a given host adapter will accept. 287 */ 288 int can_queue; 289 290 /* 291 * In many instances, especially where disconnect / reconnect are 292 * supported, our host also has an ID on the SCSI bus. If this is 293 * the case, then it must be reserved. Please set this_id to -1 if 294 * your setup is in single initiator mode, and the host lacks an 295 * ID. 296 */ 297 int this_id; 298 299 /* 300 * This determines the degree to which the host adapter is capable 301 * of scatter-gather. 302 */ 303 unsigned short sg_tablesize; 304 305 /* 306 * If the host adapter has limitations beside segment count 307 */ 308 unsigned short max_sectors; 309 310 /* 311 * dma scatter gather segment boundary limit. a segment crossing this 312 * boundary will be split in two. 313 */ 314 unsigned long dma_boundary; 315 316 /* 317 * This specifies "machine infinity" for host templates which don't 318 * limit the transfer size. Note this limit represents an absolute 319 * maximum, and may be over the transfer limits allowed for 320 * individual devices (e.g. 256 for SCSI-1) 321 */ 322 #define SCSI_DEFAULT_MAX_SECTORS 1024 323 324 /* 325 * True if this host adapter can make good use of linked commands. 326 * This will allow more than one command to be queued to a given 327 * unit on a given host. Set this to the maximum number of command 328 * blocks to be provided for each device. Set this to 1 for one 329 * command block per lun, 2 for two, etc. Do not set this to 0. 330 * You should make sure that the host adapter will do the right thing 331 * before you try setting this above 1. 332 */ 333 short cmd_per_lun; 334 335 /* 336 * present contains counter indicating how many boards of this 337 * type were found when we did the scan. 338 */ 339 unsigned char present; 340 341 /* 342 * true if this host adapter uses unchecked DMA onto an ISA bus. 343 */ 344 unsigned unchecked_isa_dma:1; 345 346 /* 347 * true if this host adapter can make good use of clustering. 348 * I originally thought that if the tablesize was large that it 349 * was a waste of CPU cycles to prepare a cluster list, but 350 * it works out that the Buslogic is faster if you use a smaller 351 * number of segments (i.e. use clustering). I guess it is 352 * inefficient. 353 */ 354 unsigned use_clustering:1; 355 356 /* 357 * True for emulated SCSI host adapters (e.g. ATAPI) 358 */ 359 unsigned emulated:1; 360 361 /* 362 * True if the low-level driver performs its own reset-settle delays. 363 */ 364 unsigned skip_settle_delay:1; 365 366 /* 367 * ordered write support 368 */ 369 unsigned ordered_flush:1; 370 unsigned ordered_tag:1; 371 372 /* 373 * Countdown for host blocking with no commands outstanding 374 */ 375 unsigned int max_host_blocked; 376 377 /* 378 * Default value for the blocking. If the queue is empty, 379 * host_blocked counts down in the request_fn until it restarts 380 * host operations as zero is reached. 381 * 382 * FIXME: This should probably be a value in the template 383 */ 384 #define SCSI_DEFAULT_HOST_BLOCKED 7 385 386 /* 387 * Pointer to the sysfs class properties for this host, NULL terminated. 388 */ 389 struct class_device_attribute **shost_attrs; 390 391 /* 392 * Pointer to the SCSI device properties for this host, NULL terminated. 393 */ 394 struct device_attribute **sdev_attrs; 395 396 /* 397 * List of hosts per template. 398 * 399 * This is only for use by scsi_module.c for legacy templates. 400 * For these access to it is synchronized implicitly by 401 * module_init/module_exit. 402 */ 403 struct list_head legacy_hosts; 404 }; 405 406 /* 407 * shost states 408 */ 409 enum { 410 SHOST_ADD, 411 SHOST_DEL, 412 SHOST_CANCEL, 413 SHOST_RECOVERY, 414 }; 415 416 struct Scsi_Host { 417 /* 418 * __devices is protected by the host_lock, but you should 419 * usually use scsi_device_lookup / shost_for_each_device 420 * to access it and don't care about locking yourself. 421 * In the rare case of beeing in irq context you can use 422 * their __ prefixed variants with the lock held. NEVER 423 * access this list directly from a driver. 424 */ 425 struct list_head __devices; 426 struct list_head __targets; 427 428 struct scsi_host_cmd_pool *cmd_pool; 429 spinlock_t free_list_lock; 430 struct list_head free_list; /* backup store of cmd structs */ 431 struct list_head starved_list; 432 433 spinlock_t default_lock; 434 spinlock_t *host_lock; 435 436 struct semaphore scan_mutex;/* serialize scanning activity */ 437 438 struct list_head eh_cmd_q; 439 struct task_struct * ehandler; /* Error recovery thread. */ 440 struct semaphore * eh_wait; /* The error recovery thread waits 441 on this. */ 442 struct completion * eh_notify; /* wait for eh to begin or end */ 443 struct semaphore * eh_action; /* Wait for specific actions on the 444 host. */ 445 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if 446 this is true. */ 447 unsigned int eh_kill:1; /* set when killing the eh thread */ 448 wait_queue_head_t host_wait; 449 struct scsi_host_template *hostt; 450 struct scsi_transport_template *transportt; 451 volatile unsigned short host_busy; /* commands actually active on low-level */ 452 volatile unsigned short host_failed; /* commands that failed. */ 453 454 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ 455 int resetting; /* if set, it means that last_reset is a valid value */ 456 unsigned long last_reset; 457 458 /* 459 * These three parameters can be used to allow for wide scsi, 460 * and for host adapters that support multiple busses 461 * The first two should be set to 1 more than the actual max id 462 * or lun (i.e. 8 for normal systems). 463 */ 464 unsigned int max_id; 465 unsigned int max_lun; 466 unsigned int max_channel; 467 468 /* 469 * This is a unique identifier that must be assigned so that we 470 * have some way of identifying each detected host adapter properly 471 * and uniquely. For hosts that do not support more than one card 472 * in the system at one time, this does not need to be set. It is 473 * initialized to 0 in scsi_register. 474 */ 475 unsigned int unique_id; 476 477 /* 478 * The maximum length of SCSI commands that this host can accept. 479 * Probably 12 for most host adapters, but could be 16 for others. 480 * For drivers that don't set this field, a value of 12 is 481 * assumed. I am leaving this as a number rather than a bit 482 * because you never know what subsequent SCSI standards might do 483 * (i.e. could there be a 20 byte or a 24-byte command a few years 484 * down the road?). 485 */ 486 unsigned char max_cmd_len; 487 488 int this_id; 489 int can_queue; 490 short cmd_per_lun; 491 short unsigned int sg_tablesize; 492 short unsigned int max_sectors; 493 unsigned long dma_boundary; 494 /* 495 * Used to assign serial numbers to the cmds. 496 * Protected by the host lock. 497 */ 498 unsigned long cmd_serial_number, cmd_pid; 499 500 unsigned unchecked_isa_dma:1; 501 unsigned use_clustering:1; 502 unsigned use_blk_tcq:1; 503 504 /* 505 * Host has requested that no further requests come through for the 506 * time being. 507 */ 508 unsigned host_self_blocked:1; 509 510 /* 511 * Host uses correct SCSI ordering not PC ordering. The bit is 512 * set for the minority of drivers whose authors actually read 513 * the spec ;) 514 */ 515 unsigned reverse_ordering:1; 516 517 /* 518 * ordered write support 519 */ 520 unsigned ordered_flush:1; 521 unsigned ordered_tag:1; 522 523 /* 524 * Optional work queue to be utilized by the transport 525 */ 526 char work_q_name[KOBJ_NAME_LEN]; 527 struct workqueue_struct *work_q; 528 529 /* 530 * Host has rejected a command because it was busy. 531 */ 532 unsigned int host_blocked; 533 534 /* 535 * Value host_blocked counts down from 536 */ 537 unsigned int max_host_blocked; 538 539 /* legacy crap */ 540 unsigned long base; 541 unsigned long io_port; 542 unsigned char n_io_port; 543 unsigned char dma_channel; 544 unsigned int irq; 545 546 547 unsigned long shost_state; 548 549 /* ldm bits */ 550 struct device shost_gendev; 551 struct class_device shost_classdev; 552 553 /* 554 * List of hosts per template. 555 * 556 * This is only for use by scsi_module.c for legacy templates. 557 * For these access to it is synchronized implicitly by 558 * module_init/module_exit. 559 */ 560 struct list_head sht_legacy_list; 561 562 /* 563 * Points to the transport data (if any) which is allocated 564 * separately 565 */ 566 void *shost_data; 567 568 /* 569 * We should ensure that this is aligned, both for better performance 570 * and also because some compilers (m68k) don't automatically force 571 * alignment to a long boundary. 572 */ 573 unsigned long hostdata[0] /* Used for storage of host specific stuff */ 574 __attribute__ ((aligned (sizeof(unsigned long)))); 575 }; 576 577 #define class_to_shost(d) \ 578 container_of(d, struct Scsi_Host, shost_classdev) 579 580 int scsi_is_host_device(const struct device *); 581 582 static inline struct Scsi_Host *dev_to_shost(struct device *dev) 583 { 584 while (!scsi_is_host_device(dev)) { 585 if (!dev->parent) 586 return NULL; 587 dev = dev->parent; 588 } 589 return container_of(dev, struct Scsi_Host, shost_gendev); 590 } 591 592 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); 593 extern void scsi_flush_work(struct Scsi_Host *); 594 595 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); 596 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); 597 extern void scsi_scan_host(struct Scsi_Host *); 598 extern void scsi_scan_single_target(struct Scsi_Host *, unsigned int, 599 unsigned int); 600 extern void scsi_rescan_device(struct device *); 601 extern void scsi_remove_host(struct Scsi_Host *); 602 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); 603 extern void scsi_host_put(struct Scsi_Host *t); 604 extern struct Scsi_Host *scsi_host_lookup(unsigned short); 605 606 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *); 607 608 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock) 609 { 610 shost->host_lock = lock; 611 } 612 613 static inline void scsi_set_device(struct Scsi_Host *shost, 614 struct device *dev) 615 { 616 shost->shost_gendev.parent = dev; 617 } 618 619 static inline struct device *scsi_get_device(struct Scsi_Host *shost) 620 { 621 return shost->shost_gendev.parent; 622 } 623 624 extern void scsi_unblock_requests(struct Scsi_Host *); 625 extern void scsi_block_requests(struct Scsi_Host *); 626 627 struct class_container; 628 /* 629 * These two functions are used to allocate and free a pseudo device 630 * which will connect to the host adapter itself rather than any 631 * physical device. You must deallocate when you are done with the 632 * thing. This physical pseudo-device isn't real and won't be available 633 * from any high-level drivers. 634 */ 635 extern void scsi_free_host_dev(struct scsi_device *); 636 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); 637 638 /* legacy interfaces */ 639 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); 640 extern void scsi_unregister(struct Scsi_Host *); 641 642 #endif /* _SCSI_SCSI_HOST_H */ 643